It is known to repair worn cylinder bores of engine blocks. If the block is composed exclusively of gray cast iron, the cylinder bore can be bored out, re-coated by thermal spraying and then finish-machined to the original dimensions.
However, if the block is composed of aluminum (or a material having similar mechanical properties), such a repair may not be readily possible. But the piston does not always run directly in the engine block material because this material may not meet higher tribological requirements and the replacement of the piston and cylinder as principal wearing components is also considerably more complex. For this reason, a cylinder liner made of a more wear resistant material is often installed in the cylinder bore of an aluminum block. In a repair, the inner surface of the liner is re-bored and superfinished by honing. Cast-iron or aluminum alloys (usually with silicon) have proven suitable as materials for cylinder liners.
Although re-coating as above is possible, there is often flaking etc. of the new material, owing, for example, to the over-spraying of the block material with the different liner material and the differing thermal properties thereof. Finish-machining of the top surface or sealing surface with respect to the cylinder head may therefore be necessary.
DE 10 2009 008 741 A1 discloses a block for an internal combustion engine having at a cylinder bore which has a double chamfer at a sealing surface with respect to a cylinder head. The double chamfer consists of first and second chamfers inclined at two different angles with respect to the cylinder bore axis. The machining of such a double chamfer is complex and expensive, as is the milling cutter used to create such a double chamfer.